UV fluorometric sensor and method for using the same

ABSTRACT

An ultraviolet (UV) fluorometric sensor measures a chemical concentration in a sample based on the measured fluorescence of the sample. The sensor includes a controller, at least one UV light source, and at least one UV detector. The sensor emits UV light in a wavelength range of 245-265 nm from the light source through the sample in an analytical area. The UV detector measures the fluorescence emission from the sample. The controller transforms output signals from the UV detector into fluorescence values or optical densities for one or more wavelengths in the wavelength range of 265-340 nm. The controller calculates the chemical concentration of the chemical in the sample based on the measured fluorescence emissions.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.12/436,593, filed May 6, 2009, which is a continuation of U.S. patentapplication Ser. No. 11/809,208, filed May 31, 2007 (issued as U.S. Pat.No. 7,550,746 on Jun. 23, 2009), which claims the benefit of U.S.Provisional Application Ser. No. 60/809,844, filed Jun. 1, 2006, theentire contents of each of which is incorporated herein by reference.

FIELD OF THE INVENTION

The invention generally relates to a fluorometric sensor for testing aliquid or gaseous sample, and more particularly to a UV fluorometricsensor for determining and monitoring chemical concentration(s) in asample.

BACKGROUND

Absorption spectroscopy is concerned with the range of electromagneticspectra absorbed by a substance. In application Ser. No. 11/311,126,filed on Dec. 20, 2005, UV/VIS spectroscopy is used to obtain absorptioninformation of a sample placed in a spectrophotometer. Ultravioletand/or visible light at a certain wavelength (or range of wavelengths)is shined through the sample. The spectrophotometer measures how much ofthe light is absorbed by the sample.

Fluorometric spectroscopy concerns detection of fluorescent spectraemitted by a sample of interest. It involves using a beam of light,usually ultraviolet (UV) light, that excites the electrons in moleculesof certain compounds in the sample and causes them to emit light of alower energy. This lower energy light is typically, but not necessarily,visible light. This technique is popular in biochemical and medicalapplications, such as confocal microscopy, fluorescence resonance energytransfer and fluorescence lifetime imaging. Molecular fluorescencespectroscopy instrumentation generally consists of a source ofexcitation radiant energy, an excitation wavelength selector, a samplecell to contain the analyte material, an emission wavelength selector, adetector with signal processor and a readout device.

There are several types of fluorometers for measuring fluorescence.Filter fluorometers use optical filters to isolate the incident lightand fluorescent light. Spectrofluorometers use diffraction gratingmonochromators to isolate the incident light and fluorescent light. Inthese devices, the spectrum consists of the intensity of emitted lightas a function of the wavelength of either the incident light (excitationspectrum) or the emitted light, or both.

In cleaning and antimicrobial operations, commercial users, such asrestaurants, hotels, food and beverage plants, grocery stores and thelike, rely upon the concentration of the cleaning or antimicrobialproduct to make the product work effectively. Failure of a cleaning orantimicrobial product to work effectively (due to concentration issues)can cause a customer or consumer to perceive the cleaning andantimicrobial product as lower quality and the commercial users beingperceived as organizations providing inferior services. In addition,they may be investigated and/or sanctioned by government regulatory andhealth agencies. Accordingly, there is a need for a system that candetermine if the concentration of a product is within a specifiedconcentration range. The same may be true for other applications, suchas water care, pest control, beverage and bottling operations, packagingoperations, and the like.

SUMMARY

Surprisingly, it has been discovered that the concentration of a productin a sample containing a chemical that exhibits fluorescencecharacteristics can be determined using a fluorometric sensor thatmeasures the fluorescence of the sample and calculates the concentrationof the chemical based on the measured fluorescence.

In one embodiment, the invention is directed to a sensor comprising anultraviolet (UV) light source that emits a first UV wavelength through asample containing a chemical that exhibits fluorescent characteristics,a UV detector that detects fluorescence emissions of the sample at asecond UV wavelength and a controller that calculates the concentrationof the chemical in the sample based on the detected fluorescenceemission.

In another embodiment, the invention is directed to a method comprisingemitting an ultraviolet (UV) light having a first UV wavelength throughan analytical area of a sample, wherein the sample contains a chemicalthat exhibits fluorescent characteristics in the analytical area,measuring a fluorescence emission of the sample at a second UVwavelength and calculating the concentration of the chemical in thesample based on the measured fluorescence emission.

The method may also include measuring a fluorescence emission of a zerosolution having zero concentration of the chemical and calculating theconcentration of the chemical in the sample based on the calculateddifference in the measured fluorescence emission of the sample and themeasured fluorescence emission of the zero solution. The method may alsoinclude determining a calibration constant found for knownconcentrations of the chemical.

The details of one or more embodiments of the invention are set forth inthe accompanying drawings and the description below. Other features ofthe invention will be apparent from the description and drawings, andfrom the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A shows a block diagram of a fluorometric sensing system 1000 formeasuring chemical concentration in a liquid or gaseous sample (e.g. asanitizer) according to the invention.

FIG. 1B shows a sanitizing system with a fluorometric sensor forsanitizer concentration measurements in a container, such as a tank.

FIG. 2A shows a measured fluorescence spectra for an OASIS 146MULTI-QUAT SANITIZER® (hereinafter “Oasis 146”) with a UV lamp.

FIG. 2B shows spectral variations in fluorescence measurement for thesame concentrations of the OASIS 146 with a UV LED.

FIG. 2C shows a measured fluorescence spectra a Pan Max Ultra LiquidDish Detergent®.

FIG. 2D shows a measured fluorescence spectra of the OASIS 146 and thedetergent.

FIG. 3A shows an enlarged view of the fluorometric sensor in FIG. 1Bwith the wall mounted display unit in FIG. 1B.

FIG. 3B shows a prospective view of another embodiment of the inventionhaving a hand held display unit connected the fluorometric sensor inFIG. 1B.

FIG. 4 shows an exploded view of the fluorometric sensor of FIG. 1B.

FIG. 5A shows a cross-sectional of the fluorometric sensor in FIG. 1Btaken through a UV lamp and a detector channel UV photodiode.

FIG. 5B shows a cross-sectional view of the fluorometric sensor in FIG.5A taken through the UV lamp and a reference channel UV photodiode alonga line A-A.

FIG. 5C shows a cross-sectional view of the fluorometric sensor in FIG.5A taken through a line B-B.

FIG. 6A is a flowchart illustrating the process by which a fluorometricsensor determines the concentration of chemical(s) in a sample.

FIG. 6B shows a cross-sectional view of a fluorometric sensor similar tothe one in FIG. 5A with an optional concave mirror to increase UVexcitation beam intensity.

FIG. 7 shows an electrical block diagram of the embodiment of theinvention depicted in FIG. 3A.

FIG. 8 shows a sensor head with a 90-degree geometry and using glassfilters and sapphire ball lenses.

FIG. 9 shows a sensor head modified from the sensor head in FIG. 8.

FIG. 10A shows a sensor head modified from the sensor head in FIG. 8 orFIG. 9 with multiple wavelength fluorescence detectors housed therein.

FIG. 10B shows a cross-sectional view of the sensor head in FIG. 10Ataken through the light source window, UV lamp and excitation filtersalong a plane A-A.

FIG. 10C shows another cross-sectional view of the sensor head in FIG.10A taken along a plane B-B.

FIG. 11A shows a sensor head modified from the sensor head in FIG. 10Awith a linear variable UV filter and a linear detector array housedtherein.

FIG. 11B shows a cross-sectional view of the sensor head in FIG. 11Ataken through the light source window along a plane C-C.

FIG. 11C shows a cross-sectional view of the sensor head in FIG. 11Ataken through the detector window alone the plane D-D.

FIG. 12 shows an embodiment of the invention with a flat bottom formeasuring sample solutions a high concentration of analyte and/or a highturbidity.

FIG. 13 shows a portable/rechargeable multi-parameter sensor with adocking station according to the invention.

FIG. 14 shows an electrical block diagram of the embodiment of FIG. 13.

FIG. 15 shows one embodiment of the fluorescence sensor head of FIG. 13.

DETAILED DESCRIPTION

The UV fluorometric sensor of the present invention determines theconcentration of a chemical in a sample. The sensor measures the UVfluorescence emission of a sample containing a chemical which hasfluorescent characteristics. The concentration of the product is thencalculated based on the fluorescence measurement(s). There are manydifferent compounds that have fluorescent characteristics to be used indifferent applications as discussed later.

To measure/monitor chemical concentrations in a sample automatically,continuously, and with a high sensitivity, the invention uses afluorometric sensor to measure fluorescence properties of thechemical(s) in the sample and calculate the chemical concentration(s) inthe sample based on the measured fluorescence values. Surprisingly, ithas been discovered that the sensor of the present invention isespecially effective over the near UV (200-380 nm wavelength).

FIG. 1A shows a block diagram of a fluorometric sensing system 1000 formeasuring chemical concentration in a liquid or gaseous sampleconcentration. The system includes a sample solution tank 1 whichcontains a sample solution 2, an automated dispenser 3 for dispensingwater and sample into the tank 1 directly from a hot water inlet 6, acold water inlet 7, a sample concentrate inlet 8 through electricalvalves 9, 10, 11 respectively or through electrical valves 12, 13, 14after mixing in a mixing device 20 placed inside of the automateddispenser 3 to mix the dispensed water and sample, a fluorometric sensor4, which can be placed inside of a test chamber 21 or directly in thesanitizing solution tank 1 (which position is shown in FIG. 1A asreference numeral 4 a), a controller 18 that controls the automateddispenser 3, a pump 19 which takes the sample solution 2 from thesolution tank 1 through an input pipe 32 to pump it through a heater 24,electrical valves 15, 16 and returns the sample solution to the solutiontank 1 through a filter 33 for filtering out any possiblecontaminations, flow sensors 25-29, a level sensor 31 that senses asolution level in the tank 1, a pressure sensor 34 that senses whetherthe filter 33 becomes clogged with contaminations, an overflow pipe 35that releases overfill solution to a drain 36, a valve 17 that releasesthe sanitizing solution 2 to the drain 36 when the solution should bereplaced for contamination of detergent, for temperatures out of aspecified range, or for having a high turbidity, a sensor cable 37 thatconnects the sensor 4 to a display unit 5, an output cable 38 thatoutputs the reading the display unit 5 to the controller 18, a displayunit power supply cable 39, and a dispenser power supply cable 40. Theheater heats the solution 2 if a temperature sensor 30 senses thetemperature lower than a preferred temperature. The fluorometric sensor4 can be placed inside the test chamber 21 inside the automateddispenser 3 (positioned as shown on the top right side of FIG. 1A) orcan be placed into the tank 1 (positioned as shown 4 a at bottom rightside of FIG. 1A). The test chamber 21 has a lid 22 and an o-ring 23 toseal the fluorometric sensor 4 therein. FIG. 1B shows a sanitizingsystem with a fluorometric sensor for sample concentration measurementsin the tank 1 where it is secured with a bracket 42. Alternatively, thefluorometric sensor 4 is mounted to the tank 1 on a sensor mountingbracket 42 (outside of the dispenser 3 as shown in FIG. 1B). When thefluorometric sensor 4 is placed in the tank 1 (as shown 4 a at bottom ofFIG. 1B), a plug 41 is inserted in the test chamber 21 and sealed withthe lid 22 and the O-ring 23, inside of the automated dispenser 3. Thesample solution 2 may be used to clean kitchen ware in a restaurant, ina laundry facility, be dispensed into a cleaning solution container,etc.

The controller 18 may have fixed hardware design and/or issoftware-driven. The testing parameters complies with ISO 7816 ATR(answer to reset) comparison table, commands, and appropriate responses,so as to be added and altered, as needed to cope with different needs ofa user. The automated dispenser 3 has an operation mode switch 43 for auser to adjust among four operation modes: a manual mode 1, a manualmode 2, an auto mode 1 and an auto mode 2. The manual mode 1 and theauto mode 1 work when the fluorometric sensor 4 is set in the testchamber 21, while the manual mode 2 and the auto mode 2 work when thefluorometric sensor 4 is set in the tank 1. The pump 19 (FIG. 1A) can beautomatically started by the controller 18 based upon low temperaturereadings under the AUTO modes, or by an user through pressing a pumpmanual start button 44 to circulate the solution from the input pipe 32to the automated dispenser 3 and then through the filter 33 to the tank1 under the Manual modes. In the manual modes, the user can press one offaucet buttons 45 to let water and/or sample through the hot water inlet6, the cold water inlet 7, and the sample concentrate inlet 8 into theautomated dispenser 3 through the electrical valves 9, 10, 11 and thenthrough the respective faucets 46 into the tank 1. An overflow pipeinsert 47 is provided for inserting the overflow pipe 35. The displayunit 5 includes a display 48 and five indication LEDs 49. A cable 51connects the controller 18 and the electrical valve 17 for draining thesolution 2. The manual mode 1 and 2 allow manually adjusting temperatureand concentration using data from the display 48 and manually pressingbuttons on the automated dispenser 3. In the auto mode 1 and 2, thecontroller 18 receives data from the flow sensors 25-29, a temperaturesensor 30, a level sensor 31, a pressure sensor 34 and automaticallyoperates with the valves 12-17, the heater 21 and the pump 19 to followa programmed algorithm and maintain the solution temperature andconcentration inside preset limits.

OASIS 146 MULTI-QUAT SANITIZER® by Ecolab Inc. (St. Paul, Minn.)(hereinafter referred to as “OASIS 146) is a mixture of alkyl dimethylbenzyl ammonium chloride and dialkyl dimethyl ammonium chloride. Thealkyl units refer to carbon chains ranging from approximately 8 to 20carbon units. The Oasis 146 quat is used against, for example,Pseudomonas aeruginosa, Staphylococcus aureus and Salmonellacholeraesuis. Active components of the OASIS 146 absorb UV radiation ina range from 200 nm to 270 nm and produce fluorescence in a range from265 nm to 330 nm. Different UV light sources can be used forfluorescence excitation. FIG. 2A shows measured fluorescence spectra ofOASIS 146 for concentrations from 0 ppm to 500 ppm in a solution (withzero impact by detergents) with excitation at 254 nm using a lowpressure mercury lamp. FIG. 2B shows measured fluorescence spectra forthe same concentrations of the OASIS 146 excited at 255 nm with a UVLED. Sanitizing solutions with the OASIS 146 may be impacted by avariety of factors including soils and detergent compounds which areoften used as a first cleaning agent in ware-washing applications. Themeasured fluorescent spectra of an example detergent (PAM MAX ULTRALIQUID DISH DETERGENT by Ecolab Inc.) are shown at FIG. 2C. Thefluorescence of the detergent is shifted to the longer UV wavelengthscompared to the OASIS 146 fluorescence. FIG. 2D shows measuredfluorescence spectra of samples having identical 200 ppm of the OASIS146 and 0 ppm, 1 ppm, 5 ppm, 10 ppm of the detergent. According topresent invention, two spectral ranges are selected to measure the OASIS146 in presence of the detergent. The first range is from approximately265 nm to 295 nm, and the second range is from approximately 295 nm to340 nm. Those two ranges can be separated by optical UV interferencefilters such that concentrations of the OASIS 146 and the detergent canbe calculated using a known calibration and a known intensity offluorescent signal from the two spectral ranges. Another embodiment ofthe invention uses several glass filters to measure fluorescence from acombination of the first and second ranges (from approximately 265 nm to340 nm) and from the second range (from approximately 295 nm to 340 nm).For example, one channel has a combination of 3 mm of UG11 glass with 2mm of WG280 glass, and another channel has a combination of 3 mm of UG11glass with 2 mm of WG295 glass.

FIG. 3A shows an enlarged view of the fluorometric sensor 4 with thewall mounted display unit 5. The five indication LEDs 49 includes a lowconcentration indicator LED 52, an overdosed solution indicator LED 53,a contaminated solution indicator LED 54, a normal operation indicatorLED 55, and a low solution temperature indicator LED 56 which light upto warn the user of any occurrence of the respective abnormal situation.The fluorometric sensor 4 has a detector window 57, a light sourcewindow 58 and a temperature sensor insert 59 set on a substantially flatbottom surface thereof. The detector window 57 and the light sourcewindow 58 are set on a surface tilted away from the flat bottom surfaceabout 45 degrees. Further details of the fluorometric sensor 4 areexplained herein with respect to FIGS. 4-5.

FIG. 3B shows a prospective view of another embodiment of the inventionhaving a hand held display unit 60 connected through the sensor cable 37to the dip-fluorometric sensor 4. The hand held display unit 60 includesa display 61, a keypad 62, a DC power connector 63 and a communicationconnector 64. The display 61 is a vacuum florescent display or a LCDdisplay. The hand held display unit 60 may connect to other externalequipment through the communication connector 64 or wirelesslycommunicate with a computer. Through communication connector 64 orwireless communication, held display unit 60 may receive modified orupdated operation or user data information.

FIG. 4 shows an exploded view of the fluorometric sensor 4. Thefluorometric sensor 4 has a housing 92, which has a sensor cover 99attached thereto through the interlocking between the threads on theouter surface of the housing 92 and the threads of a mounting nut 101.The sensor cover 99 has an O-ring groove 96 on its outer surface tointerlock with a molded strain relief 100 which has the sensor cable 37inserted therethrough. As shown in FIGS. 4 and 5A, an internal mountingwasher 93 is provided between housing 92 and the sensor cover 99. Afirst external O-ring 94 is provided between a lower edge of themounting nut 101 and the outer surface of the housing 92. An internalO-ring 95 is provided between an inner surface of the housing 92 and thesensor cover 99. A second external O-ring 102 is provided between thesensor cover 99 and an upper edge of the mounting nut 101. The housing92 has a sensor head 67 snuggly fitted thereto through a groundinginsert 85. The grounding insert 85 has O-ring grooves 86 on its outersurface for accommodating four O-rings 84 and a grounding washer 83.

Inside the housing 92, there is a connection board 79 with apreamplifier board 75 and a reference board 78 soldered thereon. Theconnection board 79 has a hole thereon for a brass tube 88 insertingtherethrough to protect UV lamp 89. The brass tube 88 is soldered into ahousing of a shielded power supply 87. The housing of the shielded powersupply 87 has a lamp power supply connector 80 on its external topsurface. The lamp power supply connector 80 is connected with aconnector 90 with a power supply cable 91.

FIG. 5A shows a cross-sectional view of the fluorometric sensor 4 takenthrough a UV lamp 89 and a detector channel UV photodiode 74. The cable37 includes the power supply cable 91 and cable wires 97. As shown inFIG. 5A, the brass tube 88 accommodates the UV mercury lamp 89 thereinand secures the lamp 89 with a lamp O-ring 105, to provide a lightsource chamber/channel. The housing of a shielded power supply 87accommodates a power supply board 103 which has a high voltagetransformer 104 and other components soldered thereon and filled with aninsulation compound 106 therein. The connection board 79 is secured intothe sensor head through two screws 82. The preamplifier board 75 isshielded in a preamplifier board shield 68. The preamplifier board 75has a sensor connector 81 soldered on the top edge to be connected witha connector 98 with cable wires 97 connected thereto. The preamplifierboard 75 has the UV photodiode 74 attached on the lower edge and coveredby a detector filter cover 71. Two glass filters (WG280, UG-11) 72, 73are provided in the detector filter cover 71 between the detector window57 and the UV photodiode 74 and facing towards the detector window 57.An excitation filter (optional) 69 is provided on an excitation filterholder 70 surrounding the light source chamber and facing towards thelight source window 58.

FIG. 5C shows a cross-sectional view of the fluorometric sensor 4 shownin FIG. 5A taken through a line B-B. The light source chamber isenlarged in FIG. 5C. The excitation filter 69 is provided between thelight source 89 and the light source window 58. The detector window 57and the light source window 58 are sapphire prismatic lenses havingspherical surfaces on one side and flat tilted surfaces on another sideof a cylindrical body.

FIG. 7 shows another embodiment of the fluorometric sensor 4 adding aconcave or flat mirror 121 into the filter holder 70 as well as oppositeto the excitation filter 69 across the light source 89 to increaseexcitation irradiation by reflecting the light emitted from the UV lamp89 towards the opposite side to the light source window 58 back towardsthe light source window 58. In one embodiment, the light sourcechamber/channel and the detector chamber/channel may have a cylindricalshape.

The UV lamp 89 may be a gas discharge lamp, a mercury lamp, a deuteriumlamp, a metal vapor lamp, a light emission diode or a plurality of lightemission diodes. Preferably, the ultraviolet lamp 89 may be a mercurylow pressure lamp with main line at 254 nm (by BHK. Inc, ClaremontCalif.) or a UV lamp such as a Krypton gas discharge lamp (by HileControls, Florida). A light emission diode (model UV LED-255 by PhotonSystems, Inc., Covina, Calif.) can be used as a light source.Optionally, an additional ultraviolet detector is used to monitorintensity of the ultraviolet lamp 89.

FIG. 5B shows a cross-sectional view of the fluorometric sensor 4 shownin FIG. 5A taken through the UV lamp 89 and a reference channel UVphotodiode 77 along a line A-A. The reference board 78 has the UVphotodiode 77 attached on the lower edge facing the UV lamp 89 and atemperature sensor 76 provided in the temperature sensor insert 59 andconnected to another side of the reference board 78.

FIG. 6A is a flowchart illustrating the process (300) by which thefluorometric sensor determines the concentration of a chemical in asample. The sensor measures a fluorescent light emission of the activemolecule that is proportional to the actual concentration of chemical(s)in a sample. A sample containing a chemical that exhibits fluorescentcharacteristics is provided in an analytical area of the sensor (302).The sensor emits an ultraviolet (UV) light having a first UV wavelengththrough the analytical area (304). The sensor measures the fluorescenceemission of the sample at a second UV wavelength (306). The sensorincludes a controller (115 in FIG. 6B, for example) that calculates theconcentration of the chemical in the sample based on the measuredfluorescence emission (308). The first wavelength may be in the range of245-265 nm. The second UV wavelength may be in the range of 265 nm to340 nm. The sensor may also measure a reference fluorescence emission ofthe sample at the first wavelength. The sensor may also measure afluorescence emission of a zero solution having zero concentration ofthe chemical. In that case, the concentration of the chemical in thesample may be calculated based on the calculated difference in themeasured fluorescence emission of the sample containing the chemical andthe measured fluorescence emission of the zero solution. Theconcentration of the sample may also be calculated based on acalibration constant determined for known concentrations of the chemicalin a calibration sample.

For example, when using ultraviolet fluorometric sensing system having amercury lamp producing a UV radiation at 254 nm, sample concentrationsmay be evaluated based upon the signals from two UV detectors. A firstdetector (fluorescent detector) measures a fluorescent value for thewavelength 280 nm±15 nm (range from 265 nm to 295 nm) and a seconddetector (reference detector) measures an intensity of UV excitation atthe wavelength 254 nm. The calculation uses the following equations:C=K _(X)(I ^(S) ₂₈₀ /I ^(S) ₂₅₄ −I ⁰ ₂₈₀ /I ⁰ ₂₅₄)

where C—an actual concentration of a chemical X (for example, asurfactant, an antimicrobial agent, etc) in a sample solution;

K_(X)- a calibration coefficient;

I^(S) ₂₈₀- an output signal from the first detector for a samplesolution;

I^(S) ₂₅₄- an output signal from the second detector for a samplesolution;

I⁰ ₂₈₀- an output signal from the first detector for a zero solution(i.e., a solution with zero concentration of the chemical); and

I⁰ ₂₅₄—an output signal from the second detector for a zero solution.K _(X) =C _(CALIBR)/(I ^(CALIBR) ₂₈₀ /I ^(CALIBR) ₂₅₄ −I ⁰ ₂₈₀ /I ⁰ ₂₅₄)

where C_(CALIBR)- a concentration of the chemical in a calibrationsolution;

I^(CALIBR) ₂₈₀- an output signal from the first detector for thecalibration solution; and

I^(CALIBR) ₂₅₄- an output signal from the second detector for thecalibration solution.

When the chemical is quat,C _(QUAT) =K _(QUAT)(I ^(S) ₂₈₀ /I ^(S) ₂₅₄ −I ⁰ ₂₈₀ /I ⁰ ₂₅₄).

FIG. 6B shows an electrical block diagram of the embodiment of theinvention depicted in FIG. 3A. The display unit 5 includes a controller115, connected to a power supply 110, amplifiers 111-114, the display48, the keypad 62, a memory 107, the indicator LEDs 52-56, communicationmeans 108, and output means 109. The power supply 110 also suppliespower to other components in the display unit 5 and the fluorometricsensor 4, except the light source 116. The light source 116 is poweredby a lamp power supply 300 which is controlled by a compact fluorescentlight bulb controller (CCFL) 310.

As mentioned above, controller 115 calculates the fluorescence valuesfor one or more wavelength ranges from 265 nm to 340 nm and determinesthe concentration of the agent using the calculated difference in thefluorescence values for one or more wavelength ranges from 265 nm to 340nm and calibration constants found for known concentrations of theagent. Operation instructions for controller 115 may be stored in memory107. In that respect, memory 107 may be a computer-readable mediumcomprising program instructions that cause controller 115 to provide anyof the functionality ascribed to them, and perform any of the methodsdescribed herein. Controller 115 may also store the raw fluorescencedata obtained by the photodiode(s) and other pertinent data in memory107. Controller 115 may also store any calculated fluorescence valuesand/or concentration data in memory 107.

The controller 115 sends synchronization signal “sync” to the CCFLcontroller 310 to coordinate operation of the fluorometric sensor. A UVlight emits from the UV lamp 89 passes through the excitation filer 69(e.g., a UV short-pass filter) and an optional focusing member 58 (FIG.5A) to an analytical area 120. The UV short-pass filter 69 is placed inthe output of a mercury lamp to transmit UV radiation for a mercuryspectral line 254 nm but reject UV radiation with longer wavelengths.Molecules of active compounds of the sample, which are present in theanalytical area 120, absorb UV radiation with a first wavelength andproduce UV fluorescence in a second wavelength range. The intensity ofthe fluorescence is proportional to concentrations of those activemolecules. The UV fluorescence passes the glass filter WG280 72 and theglass filter UG11 73 and reaches the detector channel UV photodiode 74.The glass filter WG280 72 and the glass filter UG11 73 transmit thefluorescence with wavelengths from 265 nm to 320 nm and absorb UVradiation for a mercury spectral line 254 nm, which is scattered fromthe analytical area 120 and can have an intensity higher than afluorescent signal. The photodiode 74 converts the received UVfluorescence into an electrical signal which is then amplified by apreamplifier 119 and the amplifier 112 before reaching the controller115.

The UV light emitted from the UV lamp 89 also reaches the referencechannel UV photodiode 77. The photodiode 77 converts the received lightinto an electrical signal, which is then amplified by a preamplifier 117and the amplifier 114 before reaching the controller 115. Thetemperature sensor 76 collects a temperature signal which is thenamplified by the amplifier 113 before reaching the controller 115.

The grounding insert 85 collects a conductivity signal, which has a highconductivity value when the grounding insert 59 for the temperaturesensor 76 and the grounding insert 85 both are immersed in water andwhich has a low conductivity value when one of inserts 59 or 85 is notimmersed in water. The conductivity signal is then amplified by apreamplifier 118 and by amplifier 111 before reaching the controller115. The controller 115 measures the conductivity signal and monitorsthe UV lamp according to a programmed algorithm. When the fluorometricsensor is immersed in a solution, the conductivity signal is high, thecontroller 115 turns power on for the UV lamp, and the fluorometricsensor automatically starts measurements. When fluorometric sensor istaken out of the solution, the controller 115 turns the power off forthe UV lamp thereby decreasing power consumption and extending the lamplife.

FIG. 8 shows a sensor head 122 which has 90 degree geometry using glassfilters and sapphire ball lenses, rather than the sensor head 67 have a45 degree tilted bottom surface as shown in FIG. 5A. The sensor head 122uses a sapphire ball 123 as the light source chamber window 58 as wellas focusing means, and uses another sapphire ball 124 as the detectorwindow 57 as well as focusing means to provide an analytical area 125.The sapphire balls 123, 124 are standard optical components in place ofcustom-made prismatic lenses 57, 58. The other optical components inthis embodiment are adjusted according to the deployment of the sapphireballs 123, 124 into a UV lamp 126, a brass tube 127, an excitationfilter 128 (i.e., a short-pass UV filter), a filter holder 129, areference diode 130, a glass filter UG 11 131, a glass filter WG280 132,a UV diode 133, a preamplifier board 134 and a shield 135. Those partsare identical with or similar to those shown in FIG. 5A.

FIG. 9 shows a sensor head 136, which is a modification of thefluorometric head 122 of FIG. 8 which swaps the positions of thedetector chamber and the light source chamber and provides a turbiditychannel within the detector chamber. The sensor head 136 uses a sapphireball 137 as the light source chamber window as well as focusing means,and uses another sapphire ball 138 as the detector window as well asfocusing means to provide an analytical area 139. In this embodiment,the light source chamber uses excitation filter 142, which has identicaloptical parameters with the excitation filter 128, along with an UV lamp140, a brass tube 141 and a reference diode 143. A 45-degree dichroicmirror 144 is provided to separate the fluorescence coming from theanalytical area 139 from UV radiation scattered from the analytical area139. The UV radiation from the lamp 140 passes through the excitationfilter 142 and the ball lens 137 to the analytical area 139. Thescattered UV radiation from the analytical area 139 has an identicalwavelength with the excitation UV radiation, and the dichroic mirror 144reflects it toward the turbidity channel photodiode 148. Thefluorescence form the analytical area 139 has different wavelengths fromthe excitation UV radiation, and it passes through the dichroic mirror144 to an emission filter 145 and then reaches a fluorescent channelphotodiode 147. The emission filter 145 and the dichroic mirror 144 arepositioned in an optical path between the UV detector 147 and the balllens 138, and the UV photodiode 148 is positioned perpendicular to theoptical path and directed toward a center of the dichroic mirror 144.

The emission filter 145 and the dichroic mirror 144 are supported by anemission filter holder 146. The embodiment also has a preamplifier board149 and a shield 150.

FIG. 10A shows another embodiment of a fluorometric sensor with multiplewavelength fluorescence detectors housed in a sensor head 151. Each ofthe detectors has a light source window 152 and a detector window 153,which are located in a 90 degrees cutout in the sensor head 151. Thereinall light source windows optically communicate with one gas dischargelamp and each of them forms an illuminated analytical area in front of acorresponding detector window. FIG. 10B shows a cross-sectional view ofthe sensor head 151 in FIG. 10A taken through the light source windowsalong a plane A-A. An optical filter 301-1 and optional optical filters301-2 and 301-3 are located between a gas discharge lamp and the lightsource windows 152 (which are sapphire ball lenses). In the embodimentshown in FIG. 10B, the gas discharge lamp 302 is a mercury lamp, theoptical filter 301-1 is a UV short pass filter for transmittingradiation at 254 nm, the optical filter 301-2 is a narrow band UV filterfor transmitting radiation at 296 nm, and the optical filter 301-3 is anarrow band UV filter for transmitting radiation at 365 nm. Thecombination of three wavelengths 254 nm, 296 nm and 365 nm allows thefluorometric sensor to measure many substances which have fluorescenceunder the excitation in the UV range.

FIG. 10C shows a cross-sectional view of the sensor head 151 in FIG. 10Ataken through the detector channels along a plane B-B. The photodiodes159 are soldered on a preamplifier board 160 and shielded within ashared shield 161. The shield 161 is made of a brass tube and has fiveholes 161-1 accommodating optical communication between the ball lens153 and respective photodiodes 159. Each photodiode 159 has a filterholder 404 secured on the photodiode housing. Filters 158 for thechannels installed in the filter holders 404 are optical interferencefilters or glass filters or a combination of such filters chosen toseparate appropriate wavelength for each channel. In this embodiment, afilter 159-1 is a UG-5 glass filter, a filter 159-2 is a combination ofUG-11 and WG-280 glass filters, a filter 159-3 is a combination of UG-11and WG-305 glass filters, a filter 159-4 is a combination of UG-11 andWG-335 glass filters, and a filter 159-5 is a combination of BG-40 andGG-385 glass filters.

FIG. 11A shows a sensor head 162 which is a modification of thefluorometric head 151 in FIG. 10A. Rather than five separate lightsource windows 152 and five detector windows 153, this embodimentprovides a shared light source window 163 and a shared detector window164 made of a quartz or sapphire. FIG. 11B shows a cross-sectional viewof the sensor head 162 in FIG. 11A taken through the light source window163 along a plane C-C. A UV filter 303 made of UG-5 glass is placedbetween a UV lamp 304 and the light source window 163. The UV radiationfrom the UV lamp 304 passes through the UV filter 303 and the UV window163 and produce a fluorescence in the analytical area in front of thedetector window 164. FIG. 11C shows a cross-sectional view of the sensorhead 162 in FIG. 11A taken through the detector window 164 along a planeD-D. A linear detector array 171 (S8865 by Hamamatsu, Japan) is solderedon a preamplifier board 172 for detecting multiple wavelengthfluorescence from the analytical area. The linear ultraviolet filter 170(LVF (UV) by JDSU, San Jose, Calif.) is placed between the lineardetector array 171 and the shared detector window 164, with anadditional glass filter 169 optionally sandwiched in-between. Thefluorescent/turbidity channel is shielded within a shared shield 173.The shared shield 173 is made from a brass tube having a slit toaccommodate optical communication between the analytical area and thelinear detector array 171.

FIG. 12 shows an embodiment of the invention with a flat bottom formeasuring sample solutions a high concentration of analyte of 500-5000ppm and/or a high turbidity of 10-100 NTU. Instead of the 45-degreetilted bottom surface as shown in FIG. 5A, or the 90 degree geometry asshown in FIG. 8, this embodiment provides a flat bottom for a sensorhead 174. The light source chamber on the right has a UV lamp 175, areference diode 176 (set at the same height as a opening between thelight source chamber and the detector chamber), an UV lamp holder 177,an UV lamp shield 178, a power supply shield 179, a lamp o-ring 180, asealing rubber plug 181 and a power supply board 182. The detectorchamber includes a short pass UV interference filter 183, a UV dichroicmirror 184, an light source/emission window-focusing mean (e.g., asapphire ball lens) 185, a window O-ring 187, a first insert (with anexcitation filter) 188, a mirror mount disk 189, a second insert 190, aglass filter of WG280 191, a glass filter of UG11 192, an optics insert193, a photodiode ball lens 194, and a UV photodiode 195 soldered on apreamplifier board 196 shielded in a shield 197 made of a brass tube.The first insert 188 and the second insert 190 support the mirror mountdisk 189 tilted at a 45-degree angle. The UV short pass filter 183 is aninterference filter having a high transmission for a wavelength at 254nm and a low transmission for longer wavelengths from 260 nm to 400 nm.The UV dichroic mirror 184 has a high reflection for wavelengths shorterthan 260 nm and a high transmission for wavelengths longer than 280 nm.

The sensor head 174 uses the sapphire ball 185 as both the light sourcechamber window as well as the detector window to provide an analyticalarea 186. In this embodiment, the UV radiation emitted by the lamp 175passes through the opening 320, the interference filter 183, to bereflected by the UV dichroic mirror 184 to the sapphire ball 185, andthen arrives at the analytical area 186. The UV radiation in theanalytical area 186 produces a fluorescence. The fluorescent UV signal,which travels back to the sapphire ball 185, has wavelengths longer than280 nm and passes through the UV dichroic mirror 184, the glass filters191, 192 and the photodiode ball lens 194, and finally reaches the UVphotodiode 195. The reference diode 176 measures an intensity of UVradiation from the UV lamp 175 to provide a correction for thefluorescent signal, which is proportional to a concentration of analytein the analytical area 186. The analytical area 186 is closer to thebottom of the sensor head 174 than the analytical area 139 to the 90degree geometry of the sensor head 136 (FIG. 9) or the analytical areato the 45-degree tilted bottom of the sensor head 67 (FIG. 5A). Thisembodiment measures a fluorescent signal in very close proximity to thefocusing sapphire ball lens 185 and provides a higher sensitivity formeasuring fluorescence in solutions with a high turbidity or with a highanalyte concentration, where the excitation radiation and thefluorescent radiation can not travel for a long distance due to highattenuation. There is another variant embodiment where, instead of oneset of filters 191 and 192 and one photodiode 195, several sets offilters and several photodiodes or a linear detector array are used tomeasure fluorescent signals for several wavelengths.

FIG. 13 shows a portable/rechargeable multi parameter sensor 199 with adocking station 200 of the invention. The embodiment combines thefluorometric sensor 4 and the display unit 5 in FIG. 3 or FIG. 4 into anintegrated rechargeable unit such that the sensor can be moved freelywithout the restraint of a power cable. The portable/rechargeable multiparameter sensor 199 is generally L-shaped to be grabbed by four fingersonto the body with a thumb up, ready to press on a keypad 209 (as with aflight simulator). The portable multi parameter sensor 199 has a sensorhead 198 on a measuring end, the keypad 209 and a display 210 on arecharging end. IR (or other wireless) communication means 215, serialcommunication means 217 and a power input 219 are provided on therecharging end to contact corresponding elements of the wall-mounteddocking station 200. Screws 220 are used to secure the inside componentsto the housing of the portable multi parameter sensor 199. The sensorhead 198 has a light source/excitation window 202, a detector window 203in its 90-degree geometry, a temperature sensor/detector 204, anoxidation reduction potential (ORP) sensor/detector 205, a pHsensor/detector 206 on its bottom surface, as well as a conductivitysensor/detector 207 (for measuring the conductivity of an analyticalsolution) and a ground pin 208 visible from its side surface. Thedocking station 200 has a docking loop for receiving the sensor 199 setin reverse L-shape. The docking station 200 can be stand alone orwall-mounted. The docking station 200 has a detachable transformer 201,a power connector 211 for connecting with the transformer 201, a USBconnector 212, an output connector 213, IR (or other wireless)communication means 214 for wireless communication with the serialcommunication means 215 of the sensor 199, docking station serialcommunication means 216 for receiving the serial communication means 217of the sensor 199, and a power charger output 218 for receiving thepower input 219 of the sensor 199. Since the sensor 199 and the dockingstation 200 have limited memory and processing resources, they mayconnect to or wirelessly communicate with a computer or other externalequipment through the USB connector 212, or the output connector 213.For example, the sensor 199 and the docking station 200 may requiremodified or updated operation or user data information.

FIG. 14 shows an electrical block diagram of the embodiment of theinvention of FIG. 13. The sensor head 198 has a connector 226 connectedwith a connector 227 of the sensor 199 thus being detachable therefromfor repair or replacement. Rechargeable batteries 230 of the sensor 199are connected to a power supply 233 of the docking station 200 throughits power input 219 connecting with the power charger output 218 of thedocking station 200. The power supply 233 of the docking station 200 isthen connected to the transformer 201 through its internal power supplyconnector 232 connecting with its externally visible power connector211. A controller 229 of the sensor 199 is connected to a controller 234of the docking station 200 through its serial communication means 217contacting with the docking station serial communication means 216.

Inside the sensor 199, there are a fluorometric sensor 221 with anoptional turbidity channel (e.g., the embodiments depicted in FIG. 9,FIG. 10B, FIG. 12 or the one shown in FIG. 15), a light source withspectral selector 222, a detector with spectral selector 223, aturbidity sensor 224, an optional electrochemical sensor 225 (e.g., anISE sensor, an ion selective electrode sensor for chlorine or nitrite,for example), a memory 228, and a reference detector 247. Inside thedocking station 200, there are a memory 235, wireless communicationmeans 236, a USB communication means 237, an output signal board 238, arelay outputs and analog outputs 239, and a calendar chip 240 (forproviding a real time stamp associated with a measurement result).

FIG. 15 shows one embodiment of the fluorescence sensor head 198 of FIG.13. The sensor head 198 has a UV LED (e.g., UV LED-255 by PhotonSystems, Inc., Covina, Calif.), a light source/turbidity channel, adetector channel, a reference channel and a channel for monitoring anoptical transmission of the ball lenses. The fluorescence sensor head198 has two ball lens 202, 203 functioning as the excitationwindow-focusing means 137 and the detector window-focusing means 138 inFIG. 9, but moves the detector chamber back to right and adds a GaNphotodiode 254 being tilted at 22.5-degree to function as a turbiditydirect light detector and a detector for optics transmittancevalidation. In the detector chamber on the right side of FIG. 15, a45-degree dichroic filter 250, a holder 251 for the 45-degree dichroicfilter 250, a glass filter 252 of model WG280, a UV photodiode 253, apreamplifier board 255, and a shield 256 are provided similarly to thecorresponding components in the left channel in FIG. 9. In the lightsource/turbidity channel on the left side of FIG. 15, a first UV LED(255 nm) 241, a second UV LED (350 nm) 245, and a GaN photodiode 247 aresoldered to a LED board 248. The first UV LED (255 nm) 241 is supportedby a short pass UV filter holder 242, and covered by a short pass UVfilter 243 to function as the fluorescence light source as the UV lampsin the above-discussed embodiments. The second UV LED (350 nm) 245 issupported by a second UV LED (350 nm) holder 244 to function as a lightsource for the optics transmittance validation channel. The GaNphotodiode 247 is supported by a GaN photodiode holder 246 to functionas a reference detector for monitoring the UV intensity of the first UVLED (255 nm) 241 and the second UV LED (350 nm) 245. The 45-degreedichroic filter 250 has a high reflection for wavelengths shorter than260 nm and a high transmission for wavelengths longer than 280 nm.

The fluorescence measuring operation of this embodiment is similar tothe embodiment depicted in FIG. 9. The first UV LED 241 emits a UVradiation of 255 nm which passes the short pass UV filter 243 and theball lens 202 to an analytical area 249, where it produces from analytea fluorescent signal with wavelengths shifted relative to the excitationwavelength and proportional to an analyte concentration. It alsoproduces a scattered signal, which has an identical wavelength as theexcitation wavelength and proportional to a turbidity of the sample.Thereafter the fluorescent signal from the analytical area 249 passesthe ball lens 203, the 45-degree dichroic filter 250, and reaches the UVphotodiode 253. The turbidity signal from analytical area 249 passes theball lens 203 reflects from, the 45-degree dichroic filter 250, andreaches the UV photodiode 254. This embodiment provides one additionaloperation of measuring the cleanness of the balls lenses 202, 203. Alight of 350 nm passes the ball lenses 202 and 203 to the GaN photodiode254 from the UV LED 245 to monitor an optical transmission of the balllenses so as to determine if the surfaces of the ball lenses werecontaminated. The reference photodiode 247 measures a signal emitted bythe UV LED (350 nm) 245 and then reflected by the ball lens 202 formonitoring the UV intensity of the UV LED (350 nm) 245. Similar to theembodiment depicted in FIG. 5B, the fluorescence sensor head 198 alsohas a temperature sensor 257 and a temperature sensor insert 261.Similar to the embodiment depicted in FIG. 13, the fluorescence sensorhead 198 also provides a ground pin 258 and a conductivity sensor 259which are connected to the LED board 248 through spring contacts 260. AnUV LED emits focused light in a desired direction, while the UV lampemits in all directions and produces unnecessary heat. By replacing theUV lamp in FIG. 9 with the UV LED (255 nm) 241 in FIG. 15, thisembodiment reduces power consumption and heat emission.

Although the embodiments discussed above are described with respect toexample wavelength ranges, it shall be understood that the invention isnot limited to particular wavelengths or wavelength ranges, and that theembodiments described herein are for exemplary only. It shall also beunderstood that although particular components may be shown anddescribed, the invention is similarly not limited to any particularcomponents or physical configurations of those components.

The techniques described in this disclosure may be implemented inhardware, software, firmware or any combination thereof. For example,various aspects of the techniques may be implemented within one or moremicroprocessors, digital signal processors (DSPs), application specificintegrated circuits (ASICs), field programmable gate arrays (FPGAs), orany other equivalent integrated or discrete logic circuitry, as well asany combinations of such components. The terms “controller,” “processor”or “processing circuitry” may generally refer to any of the foregoinglogic circuitry, alone or in combination with other logic circuitry, orany other equivalent circuitry.

When implemented in software, the functionality ascribed to the systemsand devices described in this disclosure may be embodied as instructionson a computer-readable medium such as random access memory (RAM),read-only memory (ROM), non-volatile random access memory (NVRAM),electrically erasable programmable read-only memory (EEPROM).

In general, fluorometric sensors are more sensitive than absorbancesensors. In other words, less fluorescent material is needed to obtain ameasurement using a fluorometric sensor than if the same material wasmeasured using an absorbance sensor. This allows the fluorescent sensorto be used with low concentration products where absorbance sensorswould not be effective.

Additionally, the nature of fluorescent sensor allows flexibility withregard to the placement of the sensor. Specifically, an absorbancesensor requires a linear path where light is shined through a cell. Thefluorescent sensor of the present invention does not require a linearpath and can therefore be used like a port where the port can simply beplaced in a liquid or gaseous medium and provide a measurement. Thisallows flexibility if the fluorescent sensor is placed for example in awarewashing machine, sink, mop bucket, laundry machine and the like.

A fluorescent sensor also has increased specificity due to selection ofspecific absorption and emission wavelengths compared to an absorbancesensor which only selects the absorbance wavelength. This allows fordirect measurement of a fluorescent material (versus inferringconcentration through the measurement of a tracer). Additionally, thefluorometric sensors of the present invention may be used to determinethe presence of compounds or substances that are not supposed to be in aproduct or composition, for example, contaminations such as soils, hardwater, bacteria, and the like.

Determining a product concentration is useful in many applications,especially determining the product concentration of a cleaning orantimicrobial product. Cleaning and antimicrobial products are used inmany different applications including laundry, automatic ware-washing,manual ware-washing, 3^(rd) sink applications, power sink applications,vehicle care, clean-in-place operations, healthcare applications, hardsurface applications and the like. The fluorometric sensor of thepresent invention can be used to determine the concentration of thecleaning or antimicrobial product in any or all of these applications.

In laundry applications, detergent compositions, fabric softeners,fabric brighteners, antimicrobial agents and bleaches, are used to cleanand reduce the microorganism population on textiles, such as bedding,towels, clothes and uniforms. The laundry application may include homelaundry applications, laundromats, on-premise laundry facilities inhotels and motels and commercial laundry facilities. The products can bedispensed in a number of ways. Typically, product is dispensed similarto ware-washing dispensing and then the product is flushed into themachine. The products can take on a number of forms includingconcentrates and ready-to-use compositions, liquid, gel, emulsion, foam,tablet, solid, powder, water soluble film with product inside, or awoven or non-woven substrate with product adhered onto it. Additionalexamples of laundry applications are described in U.S. Pat. Nos.5,861,371, 6,253,808, 6,444,023, 6,627,592, and application Ser. Nos.10/435,342 and 10/826,825, the complete disclosures of which areincorporated by reference herein in their entirety. The sensor of thepresent invention measures fluorescence in a liquid solution or measuresfluorescence by looking through a gas (i.e., air) at a surface. Thesensor can be connected to the device or can be a fiber optic. When usedin laundry applications specifically, some non-limiting examples fordeploying the sensor of the present invention include measuring theliquid coming out of a dispenser that is flushed into the machine,measuring the liquid being pumped out of the machine after the laundrycycle is complete, or measuring liquid in the holding tank.

In ware-washing applications, detergent compositions, rinse aids,antimicrobial agents and the like are dispensed in various cycles into aware-washing machine to wash dishes, glassware, utensils, and pots andpans. The products can be dispensed into a number of types of machinesincluding traditional consumer automatic dishwashing machines andinstitutional ware-washing machines (such as door or hood machines,conveyor machines, under-counter machines, glass-washers, flightmachines, pot and pan machines, and utensil washers). The product can bedispensed using a variety of dispensing mechanisms including pumps(e.g., peristaltic, bellows, and the like), syringe/plunger injection,gravity feed, siphon feed, aspirators, unit dose (e.g., a water solublepacket such as polyvinyl alcohol, a foil pouch, a “pill” or “gum ball”dispenser that drops a tablet into the machine), evacuation from apressurized chamber, diffusion through a membrane or permeable surface,and the like. In manual ware-washing applications, product is added towater, either manually or via a dispenser, and then dishes, glassware,utensils, pots and pans are washed manually. The product may be in theform of a concentrate or ready-to-use composition, and may be a liquid,gel, emulsion, foam, a tablet or other solid, a powder, a water-solublefilm with product inside, or a woven or non-woven substrate with productadhered or impregnated onto it.

A 3^(rd) sink refers to an additional sink in a restaurant that includesa sanitizer. Once a dish, glass, utensil, pot or pan is washed manually,it is placed in a 3^(rd) sink to be sanitized. A power sink refers to asink that has a pump or other means of providing agitation to the water.It is a cross between an automatic ware-washing machine and manualware-washing and can be found in quick service restaurants. Productsused in power sink applications are similar to those used in manualware-washing applications although they may be formulated slightlydifferent to account for the unique characteristics of a power sinkapplication such as foam generation. The products used in power sinkapplications can be dispensed in a manner similar to manual ware-washingapplications. Additional examples of ware-washing applications aredescribed in U.S. Pat. Nos. 5,358,653, 5,880,089, 6,150,324, 6,177,392,6,258,765, 6,294,515, 6,436,893, 6,503,879, 6,583,094 6,653,266 andRE32,818, the complete disclosures of which are incorporated byreference herein in their entirety. Some non-limiting examples fordeploying the sensor in ware-washing applications include measuring inthe solution coming out of the dispenser and/or going into theware-washing machine, in the machine itself, in the sump, in thesolution being pumped out of the ware-washing machine, and in a sinksuch as a power sink, a 3^(rd) sink, or a manual washing sink.

In vehicle care applications, products such as detergents, sheetingcompositions, waxes, glass cleaners, wheel cleaners, rust inhibitors,Rain-X, and clear coat-protectants are applied to vehicles (e.g.,consumer vehicles, commercial vehicles, rental vehicles, fleet vehicles,etc.). The products may be applied manually or as part of a car washincluding automatic car washes, tunnel car washes and the like. Theseproducts are dispensed manually into a spray bottle, or bucket, orautomatically such as through a dispenser such as that described abovewith respect to ware-washing. The product may be applied to a vehiclemanually by spraying or wiping, or may be applied automatically byspraying. Additional examples of vehicle care applications are describedin U.S. Pat. Nos. 5,871,590 6,339,054, 6,645,924, 6,726,779, 6,821,351and 6,864,220, the complete disclosures of which are incorporated byreference herein in their entirety. Some non-limiting examples fordeploying the sensor in vehicle care applications include mounted on thewall or spray arm measuring the surface of the car through the air,measuring in bucket or spray bottle, measuring in the automatic spraywashing arm of an automatic car wash, and measuring in a holding tank.

In clean-in-place (CIP) operations, detergent compositions,antimicrobials and the like are pumped through a circuit. Thecombination of the chemistry and mechanical action of the compositionscleans the inside of the circuit without requiring the entire circuit tobe disassembled and cleaned manually which is very time consuming andlabor intensive. CIP cleaning is used, for example, to clean food andbeverage, pharmaceutical, and cosmetic processing equipment. A moredetailed discussion of CIP operations is found in U.S. Pat. Nos.5,858,117, 6,197,739, 6,953,507 and 6,991,685, the complete disclosuresof which are incorporated by reference herein in their entirety. Somenon-limiting examples for deploying the sensor in clean-in-placeapplications include measuring in the CIP circuit such as in a pipe ortank or vessel, in the line after the product is dispensed but prior toputting the product in the CIP circuit, and in the line as product isbeing pumped out of the circuit.

In healthcare settings, detergents, antimicrobials, and the like areused to meet the stringent cleaning and microorganism reduction demandsof healthcare facilities, such as hospitals, nursing homes and long termcare facilities, dental offices, clinics, and surgical suites.Detergents and antimicrobials are used to clean and disinfect textiles,such as bedding, towels, clothes, uniforms, and patient garments, hardsurfaces (such as floors, walls, countertops, beds, and bathroom,operating room and patient room fixtures), and medical instruments (suchas surgical instruments, dental instruments, examination instruments,and endoscopes). A more detailed description of healthcare applicationsis found in U.S. Pat. Nos. 4,994,200 5,223,166, 5,234,832, 5,403,5056,627,657, 6,908,891 and 6,998,369, the complete disclosures of whichare incorporated by reference herein in their entirety. Somenon-limiting examples for deploying the sensor in healthcareapplications include those already described with respect to laundryfacilities and ware-washing applications. Hard surface applications aredescribed in greater detail as follows,

In hard-surface applications, glass-cleaners, floor cleaners,antimicrobials, degreasers, multipurpose cleaners and the like are usedto clean and reduce microorganisms on hard-surfaces including but notlimited to floors, walls, countertops, room fixtures, drains, etc. Hardsurface cleaners and antimicrobials can be applied to the hard-surfacesby spraying, misting, wiping, rolling, fogging and mopping. The cleaneror antimicrobial can be a liquid, gel, emulsion, concentrate,ready-to-use solution, or can be adhered or impregnated onto a woven ornon-woven textile. The cleaner or antimicrobial can be a solid, powderor prill that is added to a liquid to form a use solution. A moredetailed description of hard-surface applications is found in U.S. Pat.Nos. 5,019,346, 5,200,189, 5,312,624, 5,314,687, 5,234,719, 5,437,868,5,489,434, 5,718,910, 6,197,321, 6,268,324, 6,472,358, 6,530,383 and6,630,434, the complete disclosures of which are incorporated byreference herein in their entirety. Some non-limiting examples fordeploying the sensor c in hard-surface applications include measuring ina spray bottle, in a bucket, and on a handheld sensor or wand.

Additionally, the sensor can be used to determine the concentration of apesticide in pest control operations. A more detailed description ofpest applications is found in U.S. Pat. Nos. 5,464,613, 5,820,855,5,914,105, 6,153,181, 6,564,502, 6,725,597, 6,877,270 and 6,937,156, thecomplete disclosures of which are incorporated by reference herein intheir entirety. For example, for a pesticide sprayed in a room, such asaround baseboards or on fixtures, a sensor mounted on a handheld deviceor wand can be used to determine the concentration of the pesticideafter application or after a period of time has elapsed.

The sensor can also be used to determine the concentration or presenceof a floor care product, both before and after it is applied to a floor.This can be used, for example, to determine if the product on the floorneeds to be removed, if a new coating needs to be applied, and thestatus of the coating prior to application onto the floor. A moredetailed description of floor care application is found in U.S. Pat.Nos. 6,695,516, 6,799,916, 6,800,353, 6,822,030, 6,822,063, 6,828,296and 6,955,490, the complete disclosures of which are incorporated byreference herein in their entirety. Some non-limiting examples fordeploying the sensor in floor care applications include incorporatedonto or into a handheld sensor or wand that can measure the fluorescenceof a floor care composition on a floor, and measuring the floor carecomposition packaging before it is applied to a floor.

The sensor can be used to determine the concentration of an additive ina pool or spa. A more detailed description of pool and spa applicationsis found in U.S. Pat. Nos. 6,398,961 and 6,506,737, the completedisclosures of which are incorporated by reference herein in theirentirety. Some non-limiting examples for deploying the sensor in pooland spa applications include measuring inside the pool or spa.

The sensor can be used to determine the concentration of products usedto treat water such as drinking water, heating water, cooling water andwastewater. A more detailed description of water care applications isfound in U.S. Pat. Nos. 6,398,961, 6,506,737 and 6,555,012, the completedisclosures of which are incorporated by reference herein in theirentirety. Some non-limiting examples for deploying the sensor in watercare applications include measuring in the water circuit or beingincorporated into a handheld sensor or wand that can be placed into thewater.

The sensor can be used to determine the concentration of anantimicrobial for application on meat carcasses. A more detaileddescription of carcass treatment is found in U.S. Pat. Nos. 5,122,538,5,200,189, 5,314,687, 5,437,868, 5,489,434, 5,718,910, 6,010,729,6,103,286, 6,113,963, 6,183,807 6,514,556 and 6,545,047, the completedisclosures of which are incorporated by reference herein in theirentirety. Some non-limiting examples for deploying the sensor in carcassapplications include measuring in a dip tank, in a chiller, incorporatedinto a handheld device or wand that can be placed in a solution such asa dip tank, in a spray cabinet prior to application onto a carcass, andmeasuring in the spray cabinet looking at the carcass after product hasbeen applied.

The sensor can be used to determine the concentration of anantimicrobial used in aseptic packaging operations and bottle washingoperations. In aseptic packaging and bottle washing operations,containers are inverted and sprayed with a solution which is thendrained out. The product is collected and re-circulated for applicationonto new bottles or packages. A more detailed description of asepticpackaging and bottle washing operations is found in U.S. Pat. Nos.6,326,032, 6,530,386, 6,593,283 and 6,998,369, the complete disclosuresof which are incorporated by reference herein in their entirety. Somenon-limiting examples for deploying the sensor in aseptic packaging andbottle washing operations includes measuring in the recirculation tank,looking at the bottles, and measuring in the line prior to applicationonto the bottles or packages.

The sensor can be used to determine the concentration of a lubricant infood or beverage conveying operations. In food or beverage plants,lubricants are needed to lubricate the interface between the package andthe conveyor. A more detailed description of lubricant technology isfound in U.S. Pat. Nos. 5,391,308, 5,932,526, 6,372,698, 6,485,794,6,495,494 and 6,667,283, the complete disclosures of which areincorporated by reference herein in their entirety. Some non-limitingexamples for deploying the sensor include measuring above the conveyorafter the lubricant is applied but before the packages are placed on theconveyor, or measuring after the packages are moved off the conveyor butbefore lubricant is applied.

The sensor of the present invention can be used to sense a wide varietyof products used in the applications described above because many of thecompounds that make up the products have fluorescent characteristics.

Generally, a compound or molecule that has a benzene component

multiple conjugated bonds, electron donating groups such as —OH, —NH₂,and —OCH₃, and polycyclic compounds exhibit fluorescent characteristics.Many compounds used in the above-described applications include chemicalstructures like these, such as surfactants, lubricants, antimicrobialagents, solvents, hydrotropes, antiredeposition agents, dyes, corrosioninhibitors and bleaching additives. These compounds can be incorporatedinto products like ware-washing detergents, rinse aids, laundrydetergents, clean-in-place cleaners, antimicrobials, floor coatings,meat, poultry and seafood carcass treatments, pesticides, vehicle carecompositions, water care compositions, pool and spa compositions,aseptic packaging compositions, bottle washing compositions, and thelike.

Some non-limiting examples of fluorescent surfactants include aromaticphosphate esters, nonyl and octylphenol alkoxylates, alkylbenzenesulfonate, sodium xylene sulfonate, sodium toluene sulfonate, sodiumcumene sulfonate, ethoxylated alkyl phenol sulfonates, alkyl naphthalenesulfonates, naphthalene sulfonate formaldehyde condensates,benzothiazole, benzotriazole, aromatic hydrocarbons, benzoic acid,sodium benzoate, sodium salicylate para-chloro-meta-xylenol, orthophenylphenol, fragrances, chlorobisphenols.

Some non-limiting examples of fluorescent antimicrobial agents includealkyldimethylbenzyl ammonium chloride, glutaraldehyde, chlorophenols,amylphenol, and alkyl dimethyl benzyl ammonium saccharinate.

Some non-limiting examples of fluorescent solvents include aromatichydrocarbons.

Some non-limiting examples of fluorescent hydrotropes include linearalkyl benzene or naphthaline sulfonates such as sodium zylene sulfonate.

Some non-limiting examples of fluorescent antiredeposition agentsinclude acid anhydride copolymers such as styrene maleic anhydridecopolymers.

Some non-limiting examples of fluorescent dyes include2-naphthalenesulfonic acid, Acid Yellow 7,1,3,6,8-pyrenetetrasulfonicacid sodium salt, and fluorescein.

Some non-limiting examples of fluorescent corrosion inhibitors includebenzotriazole, tolytriazole, 5-methyl benzotriazole (5-MBz), and1-hydroxy benzotriazole.

Some non-limiting examples of fluorescent bleaching additives includephthalimido-peroxy hexanoic acid.

It is understood that compounds known to a person skilled in the artfall into the categories described above (e.g., surfactants, solvents,antimicrobial agents, and the like) and that a person skilled in the artwill be able to select those compounds that exhibit fluorescentcharacteristics to formulate cleaning and antimicrobial productsaccordingly.

The product can take on a variety of physical forms. For example, theproduct can be a concentrate or a ready-to-use composition. Theconcentrate refers to the composition that is diluted to form theready-to-use composition. The ready-to-use composition refers to thecomposition that is applied to a surface. The concentrate andready-to-use composition can be a liquid, gel, emulsion, solid, tablet,powder, prill, gas and the like. The product can be designed forinstitutional or industrial use or the product can be unit dose (e.g., aspray bottle or a unit dose container such as a foil pouch or watersoluble pouch).

Additionally, tracers can be incorporated into products that may or maynot already include naturally fluorescing compounds. Some non-limitingexamples of tracers include 2-naphthalenesulfonic acid, Acid Yellow7,1,3,6,8-pyrenetetrasulfonic acid sodium salt, and fluorescein.

As discussed, the sensor of the present invention can be placed inseveral different places in order to measure fluorescence. For example,the sensor can be placed inside a warewashing machine or laundrymachine, inside a sink, in a mop bucket, in a pipe, in a tank, mountedon another sensor or handheld device that can be placed next to a floorto read the fluorescence of a floor care composition, next to or near aspray nozzle or in the path of the spray pattern (e.g., a lubricantspray nozzle, a spray nozzle in a cabinet for treating carcasses), in ahealthcare instrument reprocessor, inside a cooling or heating tower, ina pool or spa, in or near a product dispenser, and the like.

As discussed, the sensor of the present invention can be used todetermine the concentration of a product. Accordingly, the sensor can bepart of a feedback loop where a preferred concentration is determined.If the sensor determines that the concentration is lower or higher thana threshold concentration, it can signal the dispenser to adjustappropriately by either dispensing more or less product. A feedback loopwill ensure that enough cleaner, antimicrobial or other composition ispresent to achieve the desired effect (cleanliness, reduction inmicroorganisms, lubrication, etc.).

Additionally, the sensor of the present invention can function as partof an out-of-product alarm. When a product runs out, the fluorescence(which reflects the concentration of the product) will drop below apre-determined threshold level. At this point, the sensor can generate asignal alerting an operator that the dispenser is out of product. Thesignal can be a visual or audio signal, or a vibrating signal. Thesignal can be an electronic signal that tells the machine or dispenserto stop operating until an additional amount of the product is placedinto a dispenser. The signal can be wired, for example, to a light, anaudible alarm or a dispenser. Alternatively, the signal can be wirelessand function with a dispenser or dispensers on the other side of a room,or with a web-based system. In a web-based system, a supplier, acustomer, a service providing company and/or a service technician can bealerted that a dispenser is out of product. This way, the supplier, thecustomer, the service providing company and/or the service techniciancan monitor multiple locations from one computer and dispatch someone toadd additional product.

Many principles, embodiments and modes of operation of the presentinvention have been described. However, the invention, which is intendedto be protected, is not limited to the particular embodiments disclosed.The embodiments described herein are illustrative rather thanrestrictive. Variations and changes may be made by others, andequivalents employed, without departing from the spirit of the presentinvention. These and other embodiments are within the scope of thefollowing claims.

1. A sensor, comprising: a sensor head having a bottom planar surface,the sensor head comprising: a light source chamber including anultraviolet (UV) light source that emits a first UV wavelength along afirst optical path parallel to the bottom planar surface; a dichroicmirror positioned at a 45 degree angle to the first optical path suchthat the dichroic mirror reflects the first UV wavelength toward thebottom planar surface along a second optical path perpendicular to thebottom planar surface; a window positioned in the bottom planar surfaceat a first end of the second optical path that transmits the first UVwavelength into an analytical area containing a sample having an unknownconcentration of a chemical that exhibits fluorescent characteristics,wherein the window further transmits fluorescence emissions of thesample having wavelengths greater than a second UV wavelength toward thedichroic mirror along the second optical path, wherein the dichroicmirror transmits the fluorescence emissions of the sample; and adetector chamber including a UV detector positioned at a second end ofthe second optical path that detects the fluorescence emissions of thesample transmitted by the dichroic mirror; and a controller thatcalculates the concentration of the chemical in the sample based on thedetected fluorescence emission.
 2. The sensor of claim 1 wherein thecontroller calculates the concentration of the chemical in the samplebased on a calculated difference in the detected fluorescence emissionof the sample and a detected fluorescence emission of a zero solutionhaving zero concentration of the chemical.
 3. The sensor of claim 1wherein the controller calculates the concentration of the chemical inthe sample based on the detected fluorescence emission of the sample anda calibration constant determined for known concentrations of thechemical.
 4. The sensor of claim 1 wherein the dichroic mirror has ahigh reflection for wavelengths shorter than 260 nanometers and a hightransmission for wavelengths longer than 280 nanometers.
 5. The sensorof claim 1 wherein the second UV wavelength is at least 280 nanometers.6. The sensor of claim 1 wherein the first UV wavelength is less than260 nanometers.
 7. The sensor of claim 1 wherein the chemical is anantimicrobial agent.
 8. The sensor of claim 1 wherein the sample is asolution containing the chemical, wherein the solution is a cleaning orantimicrobial solution, and wherein the chemical is selected from thegroup consisting of antimicrobial agents, surfactants, solvents,hydrotropes, antiredeposition agents, dyes, corrosion inhibitors,bleaching agents and mixtures thereof.
 9. The sensor of claim 1 whereinthe ultraviolet light source is one of a gas discharge lamp, a mercurylamp, a deuterium lamp, a metal vapor lamp, a UV light emitting diode(LED) or a plurality of UV light emitting diodes (LEDs).
 10. The sensorof claim 1 wherein the ultraviolet light source is one of a mercury lowpressure lamp with main line at about 255 nm or a Krypton gas dischargelamp.
 11. The sensor of claim 1 further comprising a reference detectorthat monitors an intensity of the UV light source.
 12. The sensor ofclaim 1 wherein the window includes one of a prismatic window or a balllens.
 13. The sensor of claim 1 further comprising at least one of areference detector, a turbidity detector, a temperature detector, anoxidation reduction potential detector, a pH detector, a conductivitydetector and an electro chemical detector.
 14. The sensor of claim 1wherein the chemical is a multi-quat sanitizer.
 15. The sensor of claim1 wherein the controller calculates the concentration of the chemical inthe sample using the equation:C=K _(X)(I ^(S) ₂₈₀ /I ^(S) ₂₅₄ −I ⁰ ₂₈₀ /I ⁰ ₂₅₄) wherein C is aconcentration of the chemical in the sample, K_(X) is a calibrationcoefficient, I^(S) ₂₈₀ is an output signal from the UV detector for thesample, I^(S) ₂₅₄ is an output signal from a reference detector for thesample, I⁰ ₂₈₀ is an output signal from the UV detector for a zerosolution, I⁰ ₂₅₄ is an output signal from the reference detector for thezero solution, andK _(X) =C _(CCALIBR) /(I ^(CALIBR) ₂₈₀ /I ^(CALIBR) ₂₅₄ −I ⁰ ₂₈₀ /I ⁰₂₅₄) where C_(CALIBR) is a concentration of the chemical in acalibration solution, I^(CALIBR) ₂₈₀ is an output signal from the UVdetector for the calibration solution and I^(CALIBR) ₂₅₄ is an outputsignal from the reference detector for the calibration solution.
 16. Thesensor of claim 1 wherein the sensor head further comprises at least oneinterference filter positioned between the UV light source and thewindow.
 17. The sensor of claim 1 wherein the window includes a balllens.
 18. The sensor of claim 1 wherein the sensor head furthercomprises at least one optical filter positioned between the dichroicmirror and the UV detector.
 19. The sensor of claim 1 wherein the sensorhead further comprises a set of optical filters positioned between thedichroic mirror and the UV detector.
 20. The sensor of claim 1 whereinthe sensor head further comprises a plurality of UV detectors eachpaired with a different one of a plurality of optical filters, whereineach UV detector/optical filter pair is tuned to measure fluorescenceemissions of the sample at different wavelengths.
 21. The sensor ofclaim 1 wherein the dichroic mirror separates the fluorescence emissionsof the sample having wavelengths greater than the second UV wavelengththat are transmitted through the window from scattered UV radiation atthe first UV wavelength transmitted through the window.
 22. The sensorof claim 1 wherein the chemical is a fluorescent tracer comprising atleast one of 2-naphthalenesulfonic acid, Acid Yellow7,1,3,6,8-pyrenetetrasulfonic acid sodium salt, and fluorescein.
 23. Asensor, comprising: a sensor head having a bottom planar surface, thesensor head comprising: an ultraviolet (UV) light source that emits afirst UV wavelength; a dichroic mirror positioned to reflect the firstUV wavelength toward the bottom planar surface; a window positioned inthe bottom planar surface that transmits the first UV wavelength into ananalytical area containing a sample having an unknown concentration of achemical that exhibits fluorescent characteristics, wherein the windowfurther transmits fluorescence emissions of the sample havingwavelengths greater than a second UV wavelength, wherein the dichroicmirror transmits the fluorescence emissions of the sample; and a UVdetector that detects the fluorescence emissions of the sample; and acontroller that calculates the concentration of the chemical in thesample based on the detected fluorescence emissions.
 24. The sensor ofclaim 23 wherein the controller calculates the concentration of thechemical in the sample based on a calculated difference in the detectedfluorescence emission of the sample and a detected fluorescence emissionof a zero solution having zero concentration of the chemical.
 25. Thesensor of claim 23 wherein the controller calculates the concentrationof the chemical in the sample based on the detected fluorescenceemission of the sample and a calibration constant determined for knownconcentrations of the chemical.
 26. The sensor of claim 23 wherein thedichroic mirror has a high reflection for wavelengths shorter than 260nanometers and a high transmission for wavelengths longer than 280nanometers.
 27. The sensor of claim 23 wherein the second UV wavelengthis 280 nanometers.
 28. The sensor of claim 23 wherein the first UVwavelength is less than 260 nanometers.
 29. The sensor of claim 23wherein the chemical is an antimicrobial agent.
 30. The sensor of claim23 wherein the sample is a solution containing the chemical, wherein thesolution is a cleaning or antimicrobial solution, and wherein thechemical is selected from the group consisting of antimicrobial agents,surfactants, solvents, hydrotropes, antiredeposition agents, dyes,corrosion inhibitors, bleaching agents and mixtures thereof.
 31. Thesensor of claim 23 wherein the ultraviolet light source is one of a gasdischarge lamp, a mercury lamp, a deuterium lamp, a metal vapor lamp, aUV light emitting diode (LED) or a plurality of UV light emitting diodes(LEDs).
 32. The sensor of claim 23 wherein the ultraviolet light sourceis one of a mercury low pressure lamp with main line at about 255 nm ora Krypton gas discharge lamp.
 33. The sensor of claim 23 furthercomprising a reference detector that monitors an intensity of the UVlight source.
 34. The sensor of claim 23 wherein the window includes oneof a prismatic window or a ball lens.
 35. The sensor of claim 23 furthercomprising at least one of a reference detector, a turbidity detector, atemperature detector, an oxidation reduction potential detector, a pHdetector, a conductivity detector and an electro chemical detector. 36.The sensor of claim 23 wherein the chemical is a multi-quat sanitizer.37. The sensor of claim 23 wherein the controller calculates theconcentration of the chemical in the sample using the equation:C=K _(X)(I ^(S) ₂₈₀ /I ^(S) ₂₅₄ −I ⁰ ₂₈₀ /I ⁰ ₂₅₄) wherein C is aconcentration of the chemical in the sample, K_(X) is a calibrationcoefficient, I^(S) ₂₈₀ is an output signal from the UV detector for thesample, I^(S) ₂₅₄ is an output signal from a reference detector for thesample, I⁰ ₂₈₀ is an output signal from the UV detector for a zerosolution, I⁰ ₂₅₄ is an output signal from the reference detector for thezero solution, andK _(X) =C _(CCALIBR)/(I ^(CALIBR) ₂₈₀ /I ^(CALIBR) ₂₅₄ −I ⁰ ₂₈₀ /I ⁰₂₅₄) where C_(CALIBR) is a concentration of the chemical in acalibration solution, I^(CALIBR) ₂₈₀ is an output signal from the UVdetector for the calibration solution and I^(CALIBR) ₂₅₄ is an outputsignal from the reference detector for the calibration solution.
 38. Thesensor of claim 23 wherein the sensor head further comprises at leastone interference filter positioned between the UV light source and thewindow.
 39. The sensor of claim 23 wherein the window includes a balllens.
 40. The sensor of claim 23 wherein the sensor head furthercomprises at least one optical filter positioned between the dichroicmirror and the UV detector.
 41. The sensor of claim 23 wherein thesensor head further comprises a set of optical filters positionedbetween the dichroic mirror and the UV detector.
 42. The sensor of claim23 wherein the sensor head further comprises a plurality of UV detectorseach paired with a different one of a plurality of optical filters,wherein each UV detector/optical filter pair is tuned to measurefluorescence emissions of the sample at different wavelengths.
 43. Thesensor of claim 23 wherein the dichroic mirror separates thefluorescence emissions of the sample transmitted through the window fromscattered UV radiation at the first UV wavelength transmitted throughthe window.
 44. The sensor of claim 23 wherein the chemical is afluorescent tracer comprising one of 2-naphthalenesulfonic acid, AcidYellow 7,1,3,6,8-pyrenetetrasulfonic acid sodium salt, and fluorescein.